If you downloaded the game through the Google Store (AOS),
You can set it up yourself so that the product is not purchased unintentionally.

■ How to set your Google Play payment password
1. Launch Google Play Store and touch the profile picture on the right side of the search window
2. Settings → User Control → Select authentication request at purchase
3. Select 'Authenticate every purchase from this device through Google Play'
4. Set the payment password for your Google account